We've been looking at this also, since we have a high-capacity engine-driven hydraulic system already in place. The weight of the actuators is quite significant. In the case of the Side-Power system, which seems to have a few advantages over the other brands, 230lb per side. These actuators are the most compact but very heavy. Just another consideration....

An obvious consideration for active fin stabilizers is their position. While this is totally in the hands of the skipper and not a drawback to the fins themselves, there have been occasions when a fin was ripped off on a rock or other obstruction. The most recent case I've heard about was during a Puget Sound-SE Alaska Grand Banks-sponsored cruise a few years ago. One of the participating boats was a GB66, a boat that in my and a lot of other people's opinions should never have been made. GB made three of them and then I guess realized their mistake and didn't make anymore. The reasons are not for this particular thread.

But during this cruise the GB66 got too close to a rock or reef either entering or leaving an anchorage, tore off one of the large fin stabilizers and the resulting hole and ingress of water threatened to sink the boat. Only the fast action of a very experienced GB rep and shipwright (IIRC) saved the day.

The moral here is not "don't use active fin stabilizers" but "don't hit anything with them." Not as much an issue I would imagine in open water or places like the Gulf or eastern seaboard, but perhaps something to keep in mind in the narrow, rocky passes and entrances we can get around here and up into BC and Alaska where the water can go from real deep to rocks in a boat length or so.

Hitting something is almost always a helmsman issue, not a boat configuration issue, but depending on where one boats having a fin projecting down and out from each side of the hull can be one more thing that's important not to forget about.

I'm going to get a quote from the Trac folks. So far I've only really investigated Naiad.

The Naiad rep sent me a fin placement document that I'm going to look over. That said, I have detailed photos available of a Wesmar fin installation on a 4788 Bayliner. This installation did not require any moving of stringers or other complicated rework. It involved a large build up area in an existing compartment.

This corresponds to what the Naiad rep told me which is that in order to spread out the load Naiad recommends a 18"X18" 1.5" hull build up. That does not sound too awful complicated. I think a competent fiberglass shop should be able to do that.

The other components of a stabilizer system are:

Hydraulic. This involves mounting a hydraulic pump to either the engine or transmission. There a reservoir, cooler, and hoses to the fin actuators.

Mounting the fin actuators is really not that difficult sounding. Drill a hole, or holes. Sandwhich the pieces together.

Mount and cable the control box to the fins, power, and any other signals it needs such as the helm control, transmission reverse sensor, etc...

When you break it down, this really does not sound all that complicated.

My background is that of an electrical, electronic, and mechanical technician/ quasi engineer.

I'm going to really think about the labor on this. I have installation details from the exact same boat as mine, so the structural engineering is complete. I could hire a good fiberglass shop to do the build up then do the rest myself.

That's something to consider.

Everything but the fiberglass is well within my existing skill set.

Interesting!!!!!

If you are handy...and it sounds like you are...fiberglass/epoxy is pretty simple/forgiving.

I was just down at Marine services in Stockton Ca and a 4588 was on the hard.I don't think the 45/4788 is as flat as my memory thought. I think going with active stabilizers will make a hell of a lot of sense. I say go for it. They make an huge improvement on the 48 LRC. I think I would go all hydraulic as it's probably more reliable. Mine are angled so as to not project beyond the gunnel. I think they improve tracking down wind immensely. Sounds like a worthwhile project.

Why not compressed air? These guys have my attention and I am considering this for Skinny Dippin'. I think for you, a 4-fin system would work well. Easy install, small footprint, lower pressures, cleaner (no oil spills), and I would bet a damn-site cheaper.

Guys, all this talk about naval engineers, is just really not how a boatyard does a retrofit, especially on an out of production boat.

If I take my boat to good recreatonal boat shipyard, what they are going to do is to beef up the area around the fins, and tie that beefed up area onto the nearest stringer.

Thats the reality of boat work. They are not going to hire a structural engineer to spend thousand of dollars on an engineering study.

While enlisting a naval engineer is the "proper" method, (I cannot argue that), it is just not how the job would get done.

The fiberglass guy will read the manual, look at the boat, and add the reinforcing pad to the inside of the hull.

Sitting at a desk behind a computer we often come up with theory on how a job should get done. When we step out from behind our screens, into the bilge we come back to reality, and get after the job.

In my boats case I have photos of where these things have went in the past. Its a pretty easy place to work in. I'm not going to do the fiberglass myself. Yes, I could learn these skills, but I don't want to learn on something this important. I'm guessing that the fiberglass reinforcement can be done for 3-4k in labor if I get things out of the way for the fiberglass guy. Thats probably in the ballpark labor wise.

Why not compressed air? These guys have my attention and I am considering this for Skinny Dippin'. I think for you, a 4-fin system would work well. Easy install, small footprint, lower pressures, cleaner (no oil spills), and I would bet a damn-site cheaper.

While I won't discount their product, I'm going to go with a larger "brand" name supplier. I have quote requests out to Naiad, Trac, and Wesmar right now.

I need to study the technical details of each system and make a decision. They all seem to make quality products.

Many times a puchase decision is based on how helpful the supplier is. Thats probably how this one will work out. If a supplier is not helpful or forthcoming with answers to my questions then it's difficult to do business with them. We'll see

Fin manufacturers don't get specific on how to reinforce the hull for the actuators as they have no interest in paying for a sunk vessel where there is a question about whether more explicit standards were adequate for the particular bit of nautical stupidity that resulted in the sinking in the first place. In ABT's case, they have this disclaimer in big black letters on the installation manual:

It is the responsibility of the installer to determine what reinforcement
measures should be taken to properly strengthen the hull to withstand
forces that may be encountered in the event that the fin, and thus the fin
shaft, strike an immovable object while the vessel is under way.
Recommendations made by American Bow Thruster are to be used as
starting guidelines only. American Bow Thruster is NOT a naval
architecture firm and is NOT qualified to advise on structural matters.
American Bow Thruster strongly recommends that you seek the advice
of a naval architect familiar with your make of vessel.

I took their advice and I think I paid about $300.00 for a naval architect to provide the specs for reinforcement. With a steel boat, it is pretty easy to do the job in a way that its unlikely to sink the boat on a grounding. ABT's fins are also 'tear away' with the internal shaft designed to break off at an identified sheer force, so the reinforcement is supposed to exceed that by the margin calculated by a naval architect. I would definitely not trust a boatyard to 'wet finger' that calculation, especially with a fiberglass boat, which is probably what happened with the GB66 Marin mentioned, with the near result of a lost vessel.

If you send me a PM, I can send you the installation manual for ABT fins, which is full of useful information for someone contemplating adding active stabilizers.

One more question I would have - you indicated that Naiad indicated a pretty small fin area, which suggests to me they are recommending a system designed to operate at speeds of 10+ knots. Is that how you use the boat in conditions requiring stabilization?

Most venders have a recommended list for glass and installation. I would have a professional person do the fiber glassing. I mean why cut corners on the important areas. Also many installers donít mind if you do some of the grunt work. I usually cut the holes, run the hose/wire, let them do the hook up and bless the system which is usually required for the warranty. Save about 25+% of the install.

I have talked to several fin representatives, and they did not recommend the fins for a slow, 6 to 10 knots, and/or they recommend large/huge fins, install Ĺ to 2/3 toward the stern. They all said for the money I would not be happy. A sister 58, Freedom, had active stabilizers which quit working, estimate cost make functional was 10+ grand, so he fiberglass the fins in place with a slight down angle which he says works about the same as when they were active/working.

Last night i sent a request for information e-mail to Wesmar, and Trac via their web sites. I have already been in contact with Naiad, and am getting their quote through my favorite boatyard.

This morning at 08:30 pacific time I got a call from the wesmar rep. I liked that. They are right on the ball.

We discussed my installation and he told me that he would look up the installation records of their installs on a Bayliner 4788. He recommended a 6 sqft fin (same as Naiad recommended)

Within an hour I had a quote in my hands for the complete system, with options for the type of computer, which would be either a one axis (roll only) or a 3 axis (roll, pitch, yaw), fin options, instruction manuals, and even the cell phone number of someone that installed and tested their system on my exact model of boat.

I am frankly very impressed with Wesmars response and customer service. This is the way I want to be treated when spending this kind of dollars. i was also very impressed that once we talked about my background,they were quite happy to support me in an owner install scenario. They told me that is pretty common with their customers to do some or most of the work themselves and contract out parts that are not in the owners skill set.

I am also admittidly very impressed with Naiads response as well. Their rep has been in good contact with me, and has responded to every question, provided manuals, etc... Also great customer service.

I have eliminated the gyro from consideration. When I expressed my concerns about being the first boat on my size getting that particular model the response was to paraphrase "I wouldn't have been selling these for the last 6 years if they didn't work". Sorry, but thats not good enough.

So, unless Trac responds very positivly, I am happy to work with either Naiad or Wesmar. Since long term support is a very critical factor I'm going to do a D&B credit check on both companies to try to get an idea of their strength.